The Subspecies of the Mountain Chickadee Part 1

The Subspecies of the Mountain Chickadee.

by Joseph Grinnell.

(Contribution From the Museum of Vertebrate Zoology of the University of California)

Fieldwork was carried on by the California Museum of Vertebrate Zoology during 1917 in the Inyo region of eastern California. In going over the collection of birds obtained, the attention of the writer was arrested by certain peculiarities evident in the Mountain Chickadees. Comparison with series from the Sierras showed the Inyo birds to be paler colored and longer tailed; and in order to appraise these differences in taxonomic terms it became necessary to a.s.semble material representative of the entire range of the species, in so far as possible. The results of the study thus undertaken are presented herewith.

The material involved in the inquiry has amounted to 464 skins of the Mountain Chickadee, derived from the following sources other than the Museum of Vertebrate Zoology: United States National Museum, through Dr.

Charles W. Richmond; United States Biological Survey, through Mr. Edward W. Nelson; and the private collections of Messrs. Edward R. Warren, Joseph and John W. Mailliard, G. Frean Morcom, Harry S. Swarth, and J.

Grinnell.

As of general interest, and in the nature of an introduction to the systematic a.n.a.lysis to follow, it may be stated that _Penthestes gambeli_ including its subspecies is throughout its range non-migratory, save as a few individuals in pairs or small companies occasionally descend in fall or early winter to lower levels closely adjacent to their mountain habitats. The range of the species roughly extends from and includes the Rocky Mountains to or nearly to the Pacific Coast, and from Alberta and British Columbia south nearly to the Mexican line--somewhat south of it in northern Lower California. Within this general area the Mountain Chickadee is by no means uniformly distributed. [Page 506] Especially towards the south is its range very "spotty," the representations on detached mountain tops being wholly isolated. Two main areas of relatively continuous distribution are, however, perceivable--the Rocky Mountain area, and the Sierra Nevada area.

[Ill.u.s.tration: Fig. 1. Map showing distribution of the races of the Mountain Chickadee in California.]

Close scrutiny of the series of specimens at hand well representing the entire Rocky Mountain area reveals no variation in phylogenetic characters from the northernmost to the southernmost stations. All show in apparently equal degree the long tail and cinnamon tinge of sides and back, these features together const.i.tuting the grounds for separate subspecific recognition of a Rocky Mountain form. On the other hand, the Sierra Nevadan center, with its own recognizable race, [Page 507] of relatively short tail, proves to have two outlying divergent forms.

These three forms are alike in their lack of any cinnamon tinge, this being replaced in two of them by a buffy tinge and in one form by leaden gray. The tail in one of the outlying forms is long, in the other short.

The habitats concerned are, respectively, the desert mountains of the Inyo region of eastern California, and the coastal mountains of southern California. This differentiation within the Pacific district, particularly within the state of California, will be better understood in its geographic bearing by reference to the accompanying map (fig. 1).

The behavior of the tail of _Penthestes gambeli_--long in the Rocky Mountain district, short in the Pacific district (see figs. 2, 3)--is paralleled in the _Penthestes atricapillus_ group of chickadees across the North American continent in about the lat.i.tude of the state of Washington. In the northern Rocky Mountains occurs the race _P. a.

septentrionalis_, with long tail; in the Pacific Coast strip of Washington and Oregon occurs the race _P. a. occidentalis_, with, among other characters, relatively short tail. Other parallels are to be found in the genera _Psaltriparus_, _Thryomanes_ and _Pipilo_.

[Ill.u.s.tration: Fig. 2. Tail of _Penthestes gambeli gambeli_ (no. 27784, Mus. Vert. Zool.; [Male], full-grown juv.; Sierra Ancha, Gila Co., Arizona; June 26, 1917). 1.00.]

[Ill.u.s.tration: Fig. 3. Tail of _Penthestes gambeli abbreviatus_ (no. 24059, Mus. Vert. Zool.; [Male], full-grown juv.; Yolla Bolly Mt., Tehama Co., California; August 5, 1913). 1.00.]

It is improbable that the fact of subspecific differentiation in _Penthestes gambeli_ has been altogether overlooked previous to the present time. A premonition of the geographic variation now formally pointed out is to be found in the early writings of Baird (1858, p.

394), who remarked that "a specimen, apparently of this species [_Parus monta.n.u.s_], from Medicine Bow creek [Wyoming], (5643,) though marked female, is larger than those from California, as shown by the measurements." Also, some of the differences in proportions in the subspecies now recognized are shown in the table of measurements given by Ridgway (1904, p. 409).

For a detailed description of the Mountain Chickadee as a _species_, the reader is referred to Ridgway (1904, p. 408).

=Penthestes gambeli gambeli= (Ridgway)

Rocky Mountain Chickadee

_Parus monta.n.u.s_ Gambel (1843, p. 259); and of authors, part.

This name preoccupied (see Ridgway, 1904, p. 409).

_Parus gambeli_ Ridgway _in_ American Ornithologists' Union Committee (1886, p. 335); and of authors, part. Subst.i.tute name.

_Parus gambeli thayeri_ Birtwell (1901, p. 166). Based on advent.i.tiously colored specimen from Albuquerque, New Mexico.

Type in United States National Museum.

_Penthestes gambeli_, of authors, part.

_Type locality._--Santa Fe, New Mexico.

_Diagnosis._--Among the four subspecies of _Penthestes gambeli_ here recognized, color alone is sufficient for distinguishing _P. gambeli gambeli_. The flanks, sides of body and back in this form are pervaded with a distinct tinge of cinnamon--more exactly, the "pinkish buff" of Ridgway (1912, pl. 29). In addition, this race shows the greatest length of tail, and slenderest bill.

_Measurements._--Average of 14 males: Wing, 70.5 mm.; tail, 70.2; exposed culmen, 8.6; depth of bill at base, 3.8. For extremes, see accompanying table.

_Note._--In this paper the length of wing is the usual chord of the folded wing as dried at the side of the body in the conventional study skin. The tail length, however, is measured from the _base_ of the uropygium to the tip of the longest pair of rectrices. It is found that in preparing specimens there is a practically uniform place for cutting off from the body the uropygium with attached feathers, and this is exactly where the tail bends back at an angle to the body in the fresh bird. The lateral rectrices are rooted evenly with the base of the dried uropygium so that the measurement of tail length thus taken becomes the distance from the extreme proximal ends of the most lateral pair of rectrices to the tips of the central pair--somewhat greater than the length of tail as given by Ridgway (1901, p. xv), the latter being the measurement from the base of the central pair of tail feathers to the tips of same. My reason for adopting this different procedure here is that more accuracy seems possible thereby, at least in the kind of material here dealt with. There is less mussing of the specimen also.

Neither depth of bill nor culmen is a practical index to degree of slenderness of bill. No ordinary method of measurement will suffice to indicate the facts as they are perceived by the eye.

As will be seen by the dates in the tables, as a rule only unworn specimens have been selected for measurement.

_Range._--The Rocky Mountain region of North. America, from eastern British Columbia and western Alberta south to western Texas, New Mexico and Arizona. _Specimens examined_, 72, from the following localities:

Alberta: Smoky Valley, 50 miles north of Jasper House, 1; Henry House, 1; 15 miles west of Henry House, 1.

British Columbia: South fork of Moose River, 1.

Montana: Gallatin County: Jefferson River, 1; Madison River, 2; Hillsdale, 2; Mystic Lake, 1; Dry Creek, 1.

Idaho: Sawtooth Lake, 1.

Wyoming: Mammoth Hot Springs, 3; Jackey's Creek, 4 miles southwest of Dubois, 1; Teton Pa.s.s, 7200 ft., 2; Salt River Mts., head of Dry Creek, 9200 ft., 1; Medicine Bow Mts., 10 200[**10,200-see Twining NM below]

ft., 1; Medicine Bow Creek, 1.

Utah: Filmore, 1.

Colorado: Loveland, 1; Middle Park, 1; Sangre de Christo Pa.s.s, 1; Fort Garland, 1; Platte Canyon, 1; Pueblo, 2; Estes Park, 1; Boulder, 2; Gold Hill, 1; Golden, 7300 ft., 1; Colorado Springs, 5; Querida, Custer County, 1; Salida, Chaffee County, 1; Crested b.u.t.te, Gunnison County, 1; Stamford, 1.

Texas: Guadalupe Mts., 6800 ft., 1; Davis Mts., 1.

New Mexico: Fort Ma.s.sachusetts, 1; Fort Wingate, 1; Albuquerque, 1; Taos Mts., 8800 ft., 1; Manzano Mts., 4; Magdalena Mts., 7000 ft., 1; Cienequilla, 1; Mt. Capitan, 1; Pecos Baldy, 1; Bear Spring Mts., 1; Shiprock, 1; Corona, 1; Twining, 12,500 ft., 1; Fulton, 1; San Mateo Mts., 9500 ft., 1.

Arizona: Fort Whipple, 1; Mt. Graham, 1; San Francisco Mt., 2; Bright Angel Spring, Kaibab Plateau, 1; Canyon Spring, 1; Santa Catalina Mts., 2; Sierra Ancha, 6500 ft., 1.

=Penthestes gambeli inyoensis=, new subspecies

Inyo Mountain Chickadee